Is your cooktop flush mounted? What size pans do you use on that burner? Those are scorch marks from overheating. It happens frequently on backsplashes. They aren’t coming out.

Are you sure it isn't a shadow/reflection? Did you remove the range grates to be sure?

Did someone move the hot grates onto the counter to clean the range?

Maybe the flame heat is radiating from the grates and causing the damage?

If you get lucky, that's just scorched sealer which may be able to be stripped off. I'd test a little oven cleaner in an inconspicuous area. Crank up the legs on that appliance, please.

Yes, your range is too low. Your range has feet that will raise it. The burners need to be proud of the counters so that the heat doesn’t scorch the counters. Raise the range by 1/2-3/4”.

Looks like a shadow, if it was heat damage to the sealer or stone. It would be in the middle of the trivets not the struts. Height looks of the cook top looks fine

Shadows are gray, not brown.